Hydraulic shock absorber



Dec. 5, 1939. A. B. cA'sPr-:R

HYDRAULIC SHOCK ABsoRER Filed March l5, 1937 f w l IIII IIIII Patented Dec. 5, 1939 nrnaamo snoox insomma y anthony a. cupa, annals, N. Y., minors Houde Engineering Corporation; Builalo, N. Y., ya corporation ot New York applicativa man 1s,- im. serial 1ra-130,850

s claims. v(ci. lssss) This invention relates to direct acting hydraulic shock absorbers, particularly to that type in which the piston rod is hollow to provide a reservoir for hydraulic fluid, the important object l oi the invention being .to provide improved valving means and arrangement for controlling the iiow ot the displaced hydraulic iluid from one side oi the piston to the other and into and out oi the reservoir.

Il The various features o! my invention will become apparent from the following specification,

taken in connection with the drawing, in which drawing: Y

Figurelisaverticaldiametricalsectionota shock absorber;

Figure 2 is a section'on plane II-'II of Figure l; and

Figure 3 is a longitudinal diametrical section of the inner end o! a shock absorber, showing a modified valving arrangement. .f

In the structure of Figures 1 and 2, the cylinder Il has the head at its inner end, and the cylinder and its head may be an integral casting.

The outer head |2 is detachable and is-secured in place by threading engagement with the cylinder end, a gasket or washer I3 being preferably interposed to prevent leakage. 'I'he cylinder is iinednby a length of tubing |4 forming smooth engagement i'or a piston Il i'rom which the piston rod i4 extends outwardly through the bore |1 of the head |2. The piston is secured by threading onto the inner end l,oil the piston rod and clamped by a lock nut I8. The piston .rod is hollow to provide reservoir space il for hydraulic iluid, and a iltting 2l threads into the outer end of the piston rod and terminates in an eye 2| by means of which the piston structure may be secured to a support such as the chassis of. an

automobile with the springs of which the shock absorber is to be associated. Theouter end ci the head I2 has the recess 22 for receiving a suitable packing assembly 23 for preventing ward movement oi' the piston. In theinner end oi the piston rod is secured a cross wall 21 having the passageway 22 controlled by a check valve u suchasaballllheldinthepassagewaybya cross pin 20. l'Ihe arrangement is` such that the ball will close the passageway 28 during inward movement of the piston, but will expose the passageway during outward movement of the piston.

The wall 21 has alsoa restricted orifice Il forvg controlling iluid ow'into the reservoir I 9l during inward movement of the piston. f The cylinder wall l 'hasa longitudinally extending channel 22 along oney side thereof, the

inner side of which is closed by the lining tube i4, the channel at its outer end being connected with the outer end oi the cylinder by a passage 23. y

'Ihe cylinder head has the cross bore I4 having connection at its vinner end with the l5 channel 22 through-the passageway 35. Intermediate its ends the cross bore is intersected' by the axially extending `passage 26 Acommunicating with the inner end of the cylinder. Adjacent 5to the inner'side ci' the passageway orspace 36 a 20 bushing yI1 is seated in the bore 34 against `a shoulder 28, the bushing forming a seat for thek inner end of a cylindrical valve plug 39. The* valve plug has a threaded outer end 40 for threadi ingthrough the head 4I Aoi' a sleeve 42 in the borev 'g5 24, the head 4| Vhaving threaded engagement with the threaded outer end-of the bore. 'I'he sleeve 42 abuts the valve seat bushing 31 and surrounds the outer end of the valvej39 Iat the space 36- and is provided withports `43 communicating .au

bushing "to define oriilce passageways 46, the 35 size of the orice passagewaysdepending upon the distance of the inner ends of the slits from the outer end of the bushing. ,l

Theouter end of the bore is closable by a` threaded plug 41 which, when removed, permits ready access to the valve threaded end in the threaded sleeve head 4| for adjustment ol the inner ends of the slits relative to the outer end of the bushing I1 for the desired size of oriilce, the valve end being provided with a cross 45 slot 48 for a screwdriver or other tool for turning the valve. The'sleeve head 4| may also have a tool-receiving slot 40 so that it may be readily screwed into the bore .24 for abutment agains the bushing I1. b

'I'he head has from for securing oi the cylinder structure to, a support such as the axle of the automotive vehicle.

Describing now the operation, during 60 the eye extending'therecompresu PATENT ori-*ICE l ausser f sion movement of the vehicle spring with which the shock absorber is associated, and inward movement of the piston in the cylinder, fluid displaced from the inner end of the cylinder will flow through the passageway 24 past the check valve 25 into the outer end of the cylinder. Owing to the volumetric differential at opposite sides of the piston on account of the volume of the pistonrod, the outery end of the cylinder cannot accommodateall of the fluid displaced from the inner end thereof, and the -surplus fluid will therefore flow into the reservoir space I9 within the piston rod by way of the orice3l, the passage 28 being then closed by the check Valve 29. The orifice 3| will meter the surplus fluid flow and will determine the shock absorbing resistance of the shock absorber during the vehicle spring compression movement.

The reservoir space I9 above the `iluid level therein may be entirely enclosed and contain air so that during flow of fluid into the reservoir through the orifice 3|the air will be compressed and form a resilient cushion for assisting in checking the piston movement. i If no air cushion is desired, a vent X open to the atmosphere may be provided at the upper end, ofthe reservoir for outflow or inflow of air asthe uid level in the reservoir changes.` The orificel would then alonedetermine the shock absorbing resistance during vehicle spring compression Inovethrough the restricted orice passage 46-into the space 5IA between the sleeve 421 and the valve, and

then through port 43 into the head space 36 and to the inner end of the cylinder, the orifice 46 metering this flow.V On account of the volumetric differential on opposite sides of the piston, there will. be suction inthe lower end of the cylinder as the piston moves outwardly, but this suction f will be relieved by the free ow of fluid from the reservoir I9 through the lpassageway 28 into vthe lower end of the cylinder.`

In the modified arrangement shown inV Figure Y 3, thecylinder 52 4has the inner end wall 53 inpassageway 58 therethrough controlled by the" check valve 59, which permits flow through the passage during inward movement ofthe piston, but checks flow therethrough in the opposite direction. The pistonfrod is hollow to provide reservoir lspace 66 for hydraulic fluid, which.

space is either closed, or vented at its upper end to atmosphere through a vent X, such as is shown in Figure 1. A cross wall 6| is seated in the piston rod a distance inwardly from the end thereof and has the passage62 controlled by a check valve 63, the wall-,having also the oriilce l 64 therethrough. Y

The cross wall 6| has the recess 65 in itsouter end and against the outer end of the wall avalve seatbushing 66 seats and is held in place by a bushing 61 abutting the outer side thereof. -The seat disk 66 has the cylindrical passageway 68 for the inner end of a valve 69 the outer end of which has threaded engagement in the bushing 61'. The valve 69 has the bore 10 therethrough. and at its inner end the valve wall has the longitudinal slits 1l cooperating with the outer side of the disk 66 to define orifice passageways 12, the size of the orifice passageway depending upon the distance between the inner ends of the slits and the outer side of ythe disk 66, the disk having preferablythe beveled sharp edge boss 66' on its lower side for presenting a-sharp edge to the ends of the slits.

` The inner end of the bushing 61 has the bore or recess 13 and has ports 14 communicating kwith the :ports 15 in the piston rod to connect 'ward movement `of the piston, fluid displaced from thev inner endv of the cylinder will I flow through the passage 58 past the check valve 59 to `the outer end of the cylinder, the surplus flow resulting jfrom the volume `differential flowing throughv the bore 10of thevalve 69 into the recess 65 and from there through the orice 64 into the ,reservoirv 60 within the piston rod.

During rebound ,movement of rthe vehicle, spring .l

and outward movement of the piston, the valve- 59 closes the passageway 58 through the piston'r and the uid displaced from the outer endof the cylinder will flow through ports 15 and 14 vinto the space 13 and from-there through the orifice passageflZ and the bore V`1i) of thevalve to the inner end of the cylinder, the orifice passage metering this flow. Any suction in the lower end of the cylinder-during outward'travel of the piston will be relieved by the free ow of fluid from.,

the reservoirk 60 through the passage` 62 and through the valve bore to the inner end of vthe cylinder.

By. unscrewing the eye fitting 54 from the cylinder end, a suitable tool ymay be appliedvin the crossslot 16 in the .outer end of thefvalve 69-for turning the threaded valve for axial adjustment thereofl relative to the seat disk 66 for the desired size of the metering orifice passage 12.

I have shownpractical and efiicient'embodiments of thefeatures of my invention, but I do not desire to be hunted tothe exact construction',

arrangement, and operation shown and'described, as changes and modiiications may bemade withoutr departing from the scope of the invention.

Iclaim as my invention:

1. Ina direct acting hydraulic a cylinder structure, a piston inl said' "cylinder structure having a piston rod extending" therefrom, said piston rod being hollow to provide hydiulic fluid reservoirspace, a fluid passageway shock I absorber, j

through the piston and a check valve closing said passageway during outward movement of -the piston in the cylinder structure, a cross wall inthe inner end of the piston rod having an'oriiice therethrough and' a passageway, a check valve permitting flow through said cross wall passageway during outward movement of the piston but closing said c ross wall passagewayvagainst'flow during inwardmovementV of the piston,l achannel extending through the cylinder structure for connecting the outer end of the cylinder with the f inner end thereof, and a metering valve interposed in said channel for metering the flow during. outward movement of the piston in the .cyi-

tending therefrom through the outer end closure, said piston rod having a bore terminating at its inner end and the outer portion of said bore providing hydraulic uid reservoir space, a bushing in the inner 'end of said bore, a valve seat wall in said bore outwardly of said'bushing, a valve having threaded engagement with said bushing and cooperable with said seat Wall to denne a restricted crice passage, said valve having a passageway communicating with said orifice and the inner end of the cylinder, ports connecting the space between said bushing and seat wall with the cylinder at the outer side of the piston whereby fluid may flow from one side of the piston to the other under control of said orice when said piston reciprocates in said cylinder. said valve by its threaded engagement in said bushing being adjustable for increasing or decreasing the size of the orice passage.

3. In a direct acting hydraulic shock absorber, a cylinder, a piston operable in said cylinder and having a piston rod extending therefrom through one end of the cylinder, the piston rod being hollow and the outer portion thereof forming a reservoir space for hydraulic iiuid, a closure wall for the inner end of said piston rod, a hollow valve plug having threaded engagement with said closure wall and extending longitudinally outwardly in the piston rod space, a seat wall within the piston rod outwardly of said closure wall, said seat wall having a bore in which the outer end of the valve plug seats, passages connecting the space between said closure wall and seat wall with the cylinder at the outer 'side of the piston, said valve having a port c( operable with the inner end of the seat wall to dene a restricted orice passage for metering the fluid flow through said hollow valve from one side of the piston to the other during reciprocation of the piston, a cross wall in said piston rod outwardly of )said seat wall and having a passageway therethrough for flow of hydraulic iluid into or out of the reservoir space during reciprocation of the piston, said valve by its threaded engagementfbeing axially adjustable for increasing or decreasing the size oi' l the oriice passage.

4. In a direct acting hydraulic shock absorber, a cylinder closed at its ends, a piston reciprocable in said cylinder and having a piston rod extending therefrom through an end closure of the cylinder, said piston having a fluid passageway therethrough and a'checkvalve opening said passage during inward movement of the piston and closing said passage during outward movement of the piston, said piston rod having a bore the outer portion of which provides a reservoirspace for hydraulic fluid, a closure wall for the inner end of said bore, a seat wall in said bore-butward ly of said closure wall, ports connecting the space between said walls with the cylinder at `the outer side of the piston, a valve plug supported in said closure wall and cooperable with said seat wall to define a iluid flow metering passage, said valve having a passageway running longitudinally therethrough and said orice passage connecting said valve passage with the space between said closure wall and seat wall whereby displaced uid.,v

flow during reciprocation of the' piston will be metered by said oriilce passage, a cross wall in the piston rod bore outwardly of saidv seat wall, said cross wall havingwa' restricted passageway for the ow of surplushydraulic uid from the inner end of the cylinder through the valve passageway and into the reservoir space during inward movement of the piston, and said cross wall having a check valve controlled passage for freer flow of uid from the reservoir space through the valve passageway and to the inner end of the cylinder during outward movement of the piston.

5. In a shock absorber of the class described, a cylinder structure, a piston structure comprising a piston and a piston rod extending therefrom, said piston rod being bored at its inner end, a closure wall for the inner end of said bore, a valve seat within said bore outwardly of said closure, a valve plug extending through said closure and adjustable thereon for cooperation with said valve seat to define a restricted fluid flow passage, said valve plug having a channel therethrough between the restricted passage and the inner en d of the cylinder, and means providing a passageway for the ilow of displaced fluid from one side of the piston to the other during relative movement of said cylinder and piston structures, said passageway including said restricted passage and the valve channel.

ANTHONY B. CASPER. 

